The form is not submitted until the trigger function returns true before the form is submitted

Look at the code

 
<form id="payForm" action="yeepaypay.html" target="_blank" method="post" onsubmit="return checkform();"> 

The onsubmit function in the example is the function that fires before the form is submitted

 
function checkform() { 
var value = $("input[name='payWay']:checked").val(); 
if (value == 1) { 
$("#alipayment").submit(); 
return false; 
} 
return true; 
} 

The form will only be submitted if it returns true, otherwise it will not be submitted